Combining Planetary Science And Astronomy To Hunt For Exoplanets

Listen to the podcast “How Planets Form” with redOrbit’s Dr. John Millis and planet-hunting expert Dr. Eric Mamajek of the University of Rochester.

Have you ever looked up at the night sky and wondered just how many of the stars you see might have planets orbiting them, and if so, what those planets might be like? Our galaxy alone contains at least 200 billion stars, and researchers have been searching effortlessly to find out just how many of these Milky Way stars have orbiting planets.

The first exoplanets, planets orbiting distant stars in our Galaxy and beyond, were discovered in the early 1990s. Since then, the count on planet-bearing stars has climbed to more than 850, thanks in part to the development of better planet-hunting telescopes such as the Kepler Space Telescope. Since its launch in 2009, the Kepler mission has discovered no less than 2,300 exoplanet candidates.

With information like this in hand, astronomers are now estimating that the Milky Way has an average of at least one planet per star, raising the probability that there are at least 200 billion exoplanets in our Galaxy alone.

This sudden emergence of thinking has brought two generally-isolated fields together: planetary science, which generally focuses on the inside of our solar system, and astronomy, which typically looks beyond it. Planetary scientists are learning to use what astronomers know about solar systems beyond ours to help formulate the origins of our solar system, while astronomers are taking a keen interest in learning what their peers know about planet formation on a galactic scale.

With this knowledge in hand, a collective of nine astronomers and planetary scientists from Caltech are forming a new Center for Planetary Astronomy, essentially combining two fields into one. This new scientific presence will help maintain collaborations between the two fields, it will help attract new funding and fellowships for young scholars, and recruit top students and postdoctoral scholars.

The collective includes the likes of planetary science professor Geoff Blake, astronomy professor Lynn Hillenbrand, and senior research associate John Carpenter, all who study planet-forming disks of gas and dust around young stars. The group also includes infamous Pluto-killer Mike Brown, the Richard and Barbara Rosenberg Professor and professor of planetary astronomy. Brown studies fossil-like rubble from such planet-forming disks.

The remaining scientists focus primarily on the planets themselves. John Johnson, an assistant professor of planetary astronomy, is concerned with detection and characterization of exoplanets, those comparable to Earth, and also studies how stars´ masses affect planet formation. Heather Knutson, assistant professor of planetary science, studies composition, temperatures, atmospheres and weather of exoplanetary bodies. Yuk Yung, the Smits Family Professor of Planetary Science, studies the atmospheres of planets. Dave Stevenson, the Marvin L. Goldberger Professor of Planetary Science, studies how planetary interiors evolve. And finally, Greg Hallinan, an assistant professor of astronomy, studies radio signals emitted from exoplanets, which may indicate the presence of magnetic fields, which could mean these exoplanets are habitable or even already contain life.

The collaboration is an exciting new step in planetary astronomy, with the possibility for major discoveries coming from the newly developed field.

“The unique combination of Caltech’s top-ranked astronomical facilities, astronomy program, and planetary science program will allow us to access the deep and broad knowledge about planets and planetary systems that only comes from such a joint endeavor,” Brown said in a statement.

“I was trained as an astronomer, but what I do is planetary science. Caltech is one of the few places where we have great conversations between the two groups. And Caltech’s resources, in terms of telescopes, give us the opportunity to move quickly and think big,” added Knutson.